Fusidic acid is an antibiotic derived from the fungus Fusidium coccineum. Fusidic acid acts by inhibition of bacterial protein synthesis by preventing translocation of the elongation factor G from the ribosome. Fusidic acid has a steroid-like structure without the unwanted side effects of a steroid.1
Pharmacokinetic and pharmacodynamic studies have shown that, contrary to other topical antibiotics such as gentamicin or mupirocin, fusidic acid reaches high antimicrobial concentration at deep skin layers after topical application either on intact or damaged epidermis.2
Several randomised controlled trials demonstrated that fusidic acid, in its various topical formulations, is very effective in treating skin infections, given its high bactericidal activity against S. aureus (including strains resistant to penicillin, methicillin, ampicillin, cloxacillin), S. epidermidis, Streptococcus pyogenes, Propionibacterium acnes, Corinebatteria, Clostridia.2
Additionally, fusidic acid presents a low risk of resistance even in methicillin-resistant S. aureus strains, a common pathogen implied in the aetiology of skin infections.2
Studies using either fusidic acid cream or ointment have shown that there is fast and effective healing of skin infections. Studies in mainly primary skin infections, such as impetigo, abscesses/boils, folliculitis, and paronychia, and including a few cases of infected wounds and other secondary infections, have demonstrated response rates of between 86% and 100%, with treatment duration or mean healing time varying between four and 7.1 days.3
A study examining the clinical efficacy of topical fusidic acid ointment applied once daily compared with that of three oral antibiotics given for five days: 150mg clindamycin, 250mg flucloxacillin or 250mg of erythromycin four times daily plus placebo ointment. A total of 90 patients with skin infections including infected wounds, paronychia, and abscesses/boils, were included. The mean healing time in patients receiving oral antibiotics was grouped and compared with that in patients using the fusidic acid ointment. A significantly more rapid healing time in soft tissue infections was shown for fusidic acid ointment compared with the oral antibiotics (7.1 days vs. 9.7 days).3
A double-blind three-arm comparative study compared the effects of fusidic acid ointment plus placebo amoxicillin, placebo fusidic acid ointment plus amoxicillin, or fusidic acid ointment plus amoxicillin in 90 patients in the treatment of furuncles, carbuncles, impetigo, and infected wounds.3
Fusidic acid ointment was as effective as amoxicillin, and there was no further improvement in clinical outcomes when the treatments were used in combination. Fusidic acid ointment is as effective as mupirocin ointment but has superior patient acceptability.3
In a study involving 354 patients with primary or secondary skin infections, randomised participants to receive either mupirocin or fusidic acid three times daily for up to seven days. There was no difference between the two preparations in outcome in either primary or secondary infections.3
However, adverse events were reported in 1% of the fusidic acid ointment group, compared with 7.4% of those using mupirocin ointment. The greasy, messy, or sticky nature of mupirocin ointment accounted for most complaints.3
Such a feature makes fusidic acid particularly useful in the management of these medical conditions. Finally, possibly due to its large steric effect, fusidic acid has proved a very low risk of contact sensitisation. Overall, data on fusidic acid efficacy, safety, sensitisation potential, resistance profile and spectrum selectivity make it a first-choice option in the treatment of primary and secondary skin infection.2
SOURCE: Specialist Forum
- Bandyopadhyay D. Topical Antibacterials in Dermatology. Indian J Dermatol, 2021.
- Bonamonte D, Fortina AB, Neri L, Patrizi A. Fusidic acid in skin infections and infected atopic eczema. G Ital Dermatol Venereol, 2014.
- Long B. Fusidic acid in skin and soft-tissue infections. Acta Derm Venereol, 2008.